1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_STRING_VIEW
11#define _LIBCPP_STRING_VIEW
12
13/*
14
15    string_view synopsis
16
17namespace std {
18
19    // 7.2, Class template basic_string_view
20    template<class charT, class traits = char_traits<charT>>
21        class basic_string_view;
22
23    template<class charT, class traits>
24    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
25
26    template<class charT, class traits>
27    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
28
29    // 7.9, basic_string_view non-member comparison functions
30    template<class charT, class traits>
31    constexpr bool operator==(basic_string_view<charT, traits> x,
32                              basic_string_view<charT, traits> y) noexcept;
33    template<class charT, class traits>
34    constexpr bool operator!=(basic_string_view<charT, traits> x,
35                              basic_string_view<charT, traits> y) noexcept;
36    template<class charT, class traits>
37    constexpr bool operator< (basic_string_view<charT, traits> x,
38                                 basic_string_view<charT, traits> y) noexcept;
39    template<class charT, class traits>
40    constexpr bool operator> (basic_string_view<charT, traits> x,
41                              basic_string_view<charT, traits> y) noexcept;
42    template<class charT, class traits>
43    constexpr bool operator<=(basic_string_view<charT, traits> x,
44                                 basic_string_view<charT, traits> y) noexcept;
45    template<class charT, class traits>
46    constexpr bool operator>=(basic_string_view<charT, traits> x,
47                              basic_string_view<charT, traits> y) noexcept;
48    // see below, sufficient additional overloads of comparison functions
49
50    // 7.10, Inserters and extractors
51    template<class charT, class traits>
52      basic_ostream<charT, traits>&
53        operator<<(basic_ostream<charT, traits>& os,
54                   basic_string_view<charT, traits> str);
55
56    // basic_string_view typedef names
57    typedef basic_string_view<char> string_view;
58    typedef basic_string_view<char8_t> u8string_view; // C++20
59    typedef basic_string_view<char16_t> u16string_view;
60    typedef basic_string_view<char32_t> u32string_view;
61    typedef basic_string_view<wchar_t> wstring_view;
62
63    template<class charT, class traits = char_traits<charT>>
64    class basic_string_view {
65      public:
66      // types
67      typedef traits traits_type;
68      typedef charT value_type;
69      typedef charT* pointer;
70      typedef const charT* const_pointer;
71      typedef charT& reference;
72      typedef const charT& const_reference;
73      typedef implementation-defined const_iterator;
74      typedef const_iterator iterator;
75      typedef reverse_iterator<const_iterator> const_reverse_iterator;
76      typedef const_reverse_iterator reverse_iterator;
77      typedef size_t size_type;
78      typedef ptrdiff_t difference_type;
79      static constexpr size_type npos = size_type(-1);
80
81      // 7.3, basic_string_view constructors and assignment operators
82      constexpr basic_string_view() noexcept;
83      constexpr basic_string_view(const basic_string_view&) noexcept = default;
84      basic_string_view& operator=(const basic_string_view&) noexcept = default;
85      template<class Allocator>
86      constexpr basic_string_view(const charT* str);
87      basic_string_view(nullptr_t) = delete; // C++2b
88      constexpr basic_string_view(const charT* str, size_type len);
89      template <class It, class End>
90      constexpr basic_string_view(It begin, End end); // C++20
91      template <class Range>
92      constexpr basic_string_view(Range&& r); // C++23
93
94      // 7.4, basic_string_view iterator support
95      constexpr const_iterator begin() const noexcept;
96      constexpr const_iterator end() const noexcept;
97      constexpr const_iterator cbegin() const noexcept;
98      constexpr const_iterator cend() const noexcept;
99      const_reverse_iterator rbegin() const noexcept;
100      const_reverse_iterator rend() const noexcept;
101      const_reverse_iterator crbegin() const noexcept;
102      const_reverse_iterator crend() const noexcept;
103
104      // 7.5, basic_string_view capacity
105      constexpr size_type size() const noexcept;
106      constexpr size_type length() const noexcept;
107      constexpr size_type max_size() const noexcept;
108      constexpr bool empty() const noexcept;
109
110      // 7.6, basic_string_view element access
111      constexpr const_reference operator[](size_type pos) const;
112      constexpr const_reference at(size_type pos) const;
113      constexpr const_reference front() const;
114      constexpr const_reference back() const;
115      constexpr const_pointer data() const noexcept;
116
117      // 7.7, basic_string_view modifiers
118      constexpr void remove_prefix(size_type n);
119      constexpr void remove_suffix(size_type n);
120      constexpr void swap(basic_string_view& s) noexcept;
121
122      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
123
124      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
125      constexpr int compare(basic_string_view s) const noexcept;
126      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
127      constexpr int compare(size_type pos1, size_type n1,
128                            basic_string_view s, size_type pos2, size_type n2) const;
129      constexpr int compare(const charT* s) const;
130      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
131      constexpr int compare(size_type pos1, size_type n1,
132                            const charT* s, size_type n2) const;
133      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
134      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
135      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
136      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
137      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
138      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
139      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
140      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
141      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
142      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
143      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
144      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
145      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
146      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
147      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
148      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
149      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
150      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
151      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
152      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
153      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
154      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
155      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
156      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
157
158      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
159      constexpr bool starts_with(charT c) const noexcept;             // C++20
160      constexpr bool starts_with(const charT* s) const;               // C++20
161      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
162      constexpr bool ends_with(charT c) const noexcept;               // C++20
163      constexpr bool ends_with(const charT* s) const;                 // C++20
164
165      constexpr bool contains(basic_string_view s) const noexcept; // C++2b
166      constexpr bool contains(charT c) const noexcept;             // C++2b
167      constexpr bool contains(const charT* s) const;               // C++2b
168
169     private:
170      const_pointer data_;  // exposition only
171      size_type     size_;  // exposition only
172    };
173
174  // basic_string_view deduction guides
175  template<class It, class End>
176    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
177  template<class Range>
178    basic_string_view(Range&&) -> basic_string_view<ranges::range_value_t<Range>>; // C++23
179
180  // 7.11, Hash support
181  template <class T> struct hash;
182  template <> struct hash<string_view>;
183  template <> struct hash<u8string_view>; // C++20
184  template <> struct hash<u16string_view>;
185  template <> struct hash<u32string_view>;
186  template <> struct hash<wstring_view>;
187
188  constexpr basic_string_view<char>     operator "" sv( const char *str,     size_t len ) noexcept;
189  constexpr basic_string_view<wchar_t>  operator "" sv( const wchar_t *str,  size_t len ) noexcept;
190  constexpr basic_string_view<char8_t>  operator "" sv( const char8_t *str,  size_t len ) noexcept; // C++20
191  constexpr basic_string_view<char16_t> operator "" sv( const char16_t *str, size_t len ) noexcept;
192  constexpr basic_string_view<char32_t> operator "" sv( const char32_t *str, size_t len ) noexcept;
193
194}  // namespace std
195
196
197*/
198
199#include <__algorithm/min.h>
200#include <__assert> // all public C++ headers provide the assertion handler
201#include <__config>
202#include <__functional/unary_function.h>
203#include <__fwd/string_view.h>
204#include <__ranges/concepts.h>
205#include <__ranges/data.h>
206#include <__ranges/enable_borrowed_range.h>
207#include <__ranges/enable_view.h>
208#include <__ranges/size.h>
209#include <__string>
210#include <compare>
211#include <iosfwd>
212#include <iterator>
213#include <limits>
214#include <stdexcept>
215#include <type_traits>
216#include <version>
217
218#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
219#  pragma GCC system_header
220#endif
221
222_LIBCPP_PUSH_MACROS
223#include <__undef_macros>
224
225
226_LIBCPP_BEGIN_NAMESPACE_STD
227
228// TODO: This is a workaround for some vendors to carry a downstream diff to accept `nullptr` in
229//       string_view constructors. This can be refactored when this exact form isn't needed anymore.
230template <class _Traits>
231_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
232inline size_t __char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
233  // This needs to be a single statement for C++11 constexpr
234  return _LIBCPP_ASSERT(__s != nullptr, "null pointer passed to non-null argument of char_traits<...>::length"), _Traits::length(__s);
235}
236
237template<class _CharT, class _Traits>
238class
239    _LIBCPP_PREFERRED_NAME(string_view)
240#ifndef _LIBCPP_HAS_NO_CHAR8_T
241    _LIBCPP_PREFERRED_NAME(u8string_view)
242#endif
243    _LIBCPP_PREFERRED_NAME(u16string_view)
244    _LIBCPP_PREFERRED_NAME(u32string_view)
245    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring_view))
246    basic_string_view {
247public:
248    // types
249    typedef _Traits                                    traits_type;
250    typedef _CharT                                     value_type;
251    typedef _CharT*                                    pointer;
252    typedef const _CharT*                              const_pointer;
253    typedef _CharT&                                    reference;
254    typedef const _CharT&                              const_reference;
255    typedef const_pointer                              const_iterator; // See [string.view.iterators]
256    typedef const_iterator                             iterator;
257    typedef _VSTD::reverse_iterator<const_iterator>    const_reverse_iterator;
258    typedef const_reverse_iterator                     reverse_iterator;
259    typedef size_t                                     size_type;
260    typedef ptrdiff_t                                  difference_type;
261    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
262
263    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
264    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
265    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
266    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
267                  "traits_type::char_type must be the same type as CharT");
268
269    // [string.view.cons], construct/copy
270    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
271    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {}
272
273    _LIBCPP_INLINE_VISIBILITY
274    basic_string_view(const basic_string_view&) _NOEXCEPT = default;
275
276    _LIBCPP_INLINE_VISIBILITY
277    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
278
279    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
280    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
281        : __data(__s), __size(__len)
282    {
283#if _LIBCPP_STD_VER > 11
284    _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
285#endif
286    }
287
288#if _LIBCPP_STD_VER > 17
289    template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
290      requires (is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
291    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
292       : __data(_VSTD::to_address(__begin)), __size(__end - __begin)
293    {
294      _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
295    }
296#endif // _LIBCPP_STD_VER > 17
297
298#if _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
299    template <class _Range>
300      requires (
301        !is_same_v<remove_cvref_t<_Range>, basic_string_view> &&
302        ranges::contiguous_range<_Range> &&
303        ranges::sized_range<_Range> &&
304        is_same_v<ranges::range_value_t<_Range>, _CharT> &&
305        !is_convertible_v<_Range, const _CharT*> &&
306        (!requires(remove_cvref_t<_Range>& d) {
307          d.operator _VSTD::basic_string_view<_CharT, _Traits>();
308        }) &&
309        (!requires {
310         typename remove_reference_t<_Range>::traits_type;
311        } || is_same_v<typename remove_reference_t<_Range>::traits_type, _Traits>)
312      )
313    constexpr _LIBCPP_HIDE_FROM_ABI
314    basic_string_view(_Range&& __r) : __data(ranges::data(__r)), __size(ranges::size(__r)) {}
315#endif // _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
316
317    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
318    basic_string_view(const _CharT* __s)
319        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
320
321#if _LIBCPP_STD_VER > 20
322    basic_string_view(nullptr_t) = delete;
323#endif
324
325    // [string.view.iterators], iterators
326    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
327    const_iterator begin()  const _NOEXCEPT { return cbegin(); }
328
329    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
330    const_iterator end()    const _NOEXCEPT { return cend(); }
331
332    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
333    const_iterator cbegin() const _NOEXCEPT { return __data; }
334
335    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
336    const_iterator cend()   const _NOEXCEPT { return __data + __size; }
337
338    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
339    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
340
341    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
342    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
343
344    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
345    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); }
346
347    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
348    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
349
350    // [string.view.capacity], capacity
351    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
352    size_type size()     const _NOEXCEPT { return __size; }
353
354    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
355    size_type length()   const _NOEXCEPT { return __size; }
356
357    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
358    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max() / sizeof(value_type); }
359
360    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
361    bool empty()         const _NOEXCEPT { return __size == 0; }
362
363    // [string.view.access], element access
364    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
365    const_reference operator[](size_type __pos) const _NOEXCEPT {
366      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos];
367    }
368
369    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
370    const_reference at(size_type __pos) const
371    {
372        return __pos >= size()
373            ? (__throw_out_of_range("string_view::at"), __data[0])
374            : __data[__pos];
375    }
376
377    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
378    const_reference front() const _NOEXCEPT
379    {
380        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
381    }
382
383    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
384    const_reference back() const _NOEXCEPT
385    {
386        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
387    }
388
389    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
390    const_pointer data() const _NOEXCEPT { return __data; }
391
392    // [string.view.modifiers], modifiers:
393    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
394    void remove_prefix(size_type __n) _NOEXCEPT
395    {
396        _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()");
397        __data += __n;
398        __size -= __n;
399    }
400
401    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
402    void remove_suffix(size_type __n) _NOEXCEPT
403    {
404        _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()");
405        __size -= __n;
406    }
407
408    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
409    void swap(basic_string_view& __other) _NOEXCEPT
410    {
411        const value_type *__p = __data;
412        __data = __other.__data;
413        __other.__data = __p;
414
415        size_type __sz = __size;
416        __size = __other.__size;
417        __other.__size = __sz;
418    }
419
420    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
421    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const
422    {
423        if (__pos > size())
424            __throw_out_of_range("string_view::copy");
425        size_type __rlen = _VSTD::min(__n, size() - __pos);
426        _Traits::copy(__s, data() + __pos, __rlen);
427        return __rlen;
428    }
429
430    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
431    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const
432    {
433        return __pos > size()
434            ? (__throw_out_of_range("string_view::substr"), basic_string_view())
435            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos));
436    }
437
438    _LIBCPP_CONSTEXPR_AFTER_CXX11 int compare(basic_string_view __sv) const _NOEXCEPT
439    {
440        size_type __rlen = _VSTD::min( size(), __sv.size());
441        int __retval = _Traits::compare(data(), __sv.data(), __rlen);
442        if ( __retval == 0 ) // first __rlen chars matched
443            __retval = size() == __sv.size() ? 0 : ( size() < __sv.size() ? -1 : 1 );
444        return __retval;
445    }
446
447    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
448    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const
449    {
450        return substr(__pos1, __n1).compare(__sv);
451    }
452
453    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
454    int compare(                       size_type __pos1, size_type __n1,
455                basic_string_view __sv, size_type __pos2, size_type __n2) const
456    {
457        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
458    }
459
460    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
461    int compare(const _CharT* __s) const _NOEXCEPT
462    {
463        return compare(basic_string_view(__s));
464    }
465
466    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
467    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const
468    {
469        return substr(__pos1, __n1).compare(basic_string_view(__s));
470    }
471
472    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
473    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const
474    {
475        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
476    }
477
478    // find
479    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
480    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
481    {
482        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
483        return __str_find<value_type, size_type, traits_type, npos>
484            (data(), size(), __s.data(), __pos, __s.size());
485    }
486
487    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
488    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT
489    {
490        return __str_find<value_type, size_type, traits_type, npos>
491            (data(), size(), __c, __pos);
492    }
493
494    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
495    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
496    {
497        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
498        return __str_find<value_type, size_type, traits_type, npos>
499            (data(), size(), __s, __pos, __n);
500    }
501
502    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
503    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT
504    {
505        _LIBCPP_ASSERT(__s != nullptr, "string_view::find(): received nullptr");
506        return __str_find<value_type, size_type, traits_type, npos>
507            (data(), size(), __s, __pos, traits_type::length(__s));
508    }
509
510    // rfind
511    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
512    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT
513    {
514        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
515        return __str_rfind<value_type, size_type, traits_type, npos>
516            (data(), size(), __s.data(), __pos, __s.size());
517    }
518
519    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
520    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT
521    {
522        return __str_rfind<value_type, size_type, traits_type, npos>
523            (data(), size(), __c, __pos);
524    }
525
526    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
527    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
528    {
529        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
530        return __str_rfind<value_type, size_type, traits_type, npos>
531            (data(), size(), __s, __pos, __n);
532    }
533
534    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
535    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
536    {
537        _LIBCPP_ASSERT(__s != nullptr, "string_view::rfind(): received nullptr");
538        return __str_rfind<value_type, size_type, traits_type, npos>
539            (data(), size(), __s, __pos, traits_type::length(__s));
540    }
541
542    // find_first_of
543    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
544    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
545    {
546        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
547        return __str_find_first_of<value_type, size_type, traits_type, npos>
548            (data(), size(), __s.data(), __pos, __s.size());
549    }
550
551    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
552    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT
553    { return find(__c, __pos); }
554
555    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
556    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
557    {
558        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
559        return __str_find_first_of<value_type, size_type, traits_type, npos>
560            (data(), size(), __s, __pos, __n);
561    }
562
563    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
564    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
565    {
566        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_of(): received nullptr");
567        return __str_find_first_of<value_type, size_type, traits_type, npos>
568            (data(), size(), __s, __pos, traits_type::length(__s));
569    }
570
571    // find_last_of
572    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
573    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
574    {
575        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
576        return __str_find_last_of<value_type, size_type, traits_type, npos>
577            (data(), size(), __s.data(), __pos, __s.size());
578    }
579
580    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
581    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT
582    { return rfind(__c, __pos); }
583
584    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
585    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
586    {
587        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
588        return __str_find_last_of<value_type, size_type, traits_type, npos>
589            (data(), size(), __s, __pos, __n);
590    }
591
592    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
593    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
594    {
595        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_of(): received nullptr");
596        return __str_find_last_of<value_type, size_type, traits_type, npos>
597            (data(), size(), __s, __pos, traits_type::length(__s));
598    }
599
600    // find_first_not_of
601    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
602    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT
603    {
604        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
605        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
606            (data(), size(), __s.data(), __pos, __s.size());
607    }
608
609    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
610    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT
611    {
612        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
613            (data(), size(), __c, __pos);
614    }
615
616    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
617    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
618    {
619        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
620        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
621            (data(), size(), __s, __pos, __n);
622    }
623
624    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
625    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
626    {
627        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
628        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
629            (data(), size(), __s, __pos, traits_type::length(__s));
630    }
631
632    // find_last_not_of
633    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
634    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
635    {
636        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
637        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
638            (data(), size(), __s.data(), __pos, __s.size());
639    }
640
641    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
642    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT
643    {
644        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
645            (data(), size(), __c, __pos);
646    }
647
648    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
649    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
650    {
651        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
652        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
653            (data(), size(), __s, __pos, __n);
654    }
655
656    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
657    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
658    {
659        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
660        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
661            (data(), size(), __s, __pos, traits_type::length(__s));
662    }
663
664#if _LIBCPP_STD_VER > 17
665    constexpr _LIBCPP_INLINE_VISIBILITY
666    bool starts_with(basic_string_view __s) const noexcept
667    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; }
668
669    constexpr _LIBCPP_INLINE_VISIBILITY
670    bool starts_with(value_type __c) const noexcept
671    { return !empty() && _Traits::eq(front(), __c); }
672
673    constexpr _LIBCPP_INLINE_VISIBILITY
674    bool starts_with(const value_type* __s) const noexcept
675    { return starts_with(basic_string_view(__s)); }
676
677    constexpr _LIBCPP_INLINE_VISIBILITY
678    bool ends_with(basic_string_view __s) const noexcept
679    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; }
680
681    constexpr _LIBCPP_INLINE_VISIBILITY
682    bool ends_with(value_type __c) const noexcept
683    { return !empty() && _Traits::eq(back(), __c); }
684
685    constexpr _LIBCPP_INLINE_VISIBILITY
686    bool ends_with(const value_type* __s) const noexcept
687    { return ends_with(basic_string_view(__s)); }
688#endif
689
690#if _LIBCPP_STD_VER > 20
691    constexpr _LIBCPP_INLINE_VISIBILITY
692    bool contains(basic_string_view __sv) const noexcept
693    { return find(__sv) != npos; }
694
695    constexpr _LIBCPP_INLINE_VISIBILITY
696    bool contains(value_type __c) const noexcept
697    { return find(__c) != npos; }
698
699    constexpr _LIBCPP_INLINE_VISIBILITY
700    bool contains(const value_type* __s) const
701    { return find(__s) != npos; }
702#endif
703
704private:
705    const   value_type* __data;
706    size_type           __size;
707};
708
709#if _LIBCPP_STD_VER > 17
710template <class _CharT, class _Traits>
711inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
712
713template <class _CharT, class _Traits>
714inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
715#endif // _LIBCPP_STD_VER > 17
716
717// [string.view.deduct]
718
719#if _LIBCPP_STD_VER > 17
720template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
721  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
722#endif // _LIBCPP_STD_VER > 17
723
724
725#if _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
726template <ranges::contiguous_range _Range>
727  basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
728#endif // _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
729
730// [string.view.comparison]
731// operator ==
732template<class _CharT, class _Traits>
733_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
734bool operator==(basic_string_view<_CharT, _Traits> __lhs,
735                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
736{
737    if ( __lhs.size() != __rhs.size()) return false;
738    return __lhs.compare(__rhs) == 0;
739}
740
741// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
742// This applies to the other sufficient overloads below for the other comparison operators.
743template<class _CharT, class _Traits, int = 1>
744_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
745bool operator==(basic_string_view<_CharT, _Traits> __lhs,
746                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
747{
748    if ( __lhs.size() != __rhs.size()) return false;
749    return __lhs.compare(__rhs) == 0;
750}
751
752template<class _CharT, class _Traits, int = 2>
753_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
754bool operator==(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
755                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
756{
757    if ( __lhs.size() != __rhs.size()) return false;
758    return __lhs.compare(__rhs) == 0;
759}
760
761
762// operator !=
763template<class _CharT, class _Traits>
764_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
765bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
766{
767    if ( __lhs.size() != __rhs.size())
768        return true;
769    return __lhs.compare(__rhs) != 0;
770}
771
772template<class _CharT, class _Traits, int = 1>
773_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
774bool operator!=(basic_string_view<_CharT, _Traits> __lhs,
775                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
776{
777    if ( __lhs.size() != __rhs.size())
778        return true;
779    return __lhs.compare(__rhs) != 0;
780}
781
782template<class _CharT, class _Traits, int = 2>
783_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
784bool operator!=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
785                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
786{
787    if ( __lhs.size() != __rhs.size())
788        return true;
789    return __lhs.compare(__rhs) != 0;
790}
791
792
793// operator <
794template<class _CharT, class _Traits>
795_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
796bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
797{
798    return __lhs.compare(__rhs) < 0;
799}
800
801template<class _CharT, class _Traits, int = 1>
802_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
803bool operator<(basic_string_view<_CharT, _Traits> __lhs,
804                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
805{
806    return __lhs.compare(__rhs) < 0;
807}
808
809template<class _CharT, class _Traits, int = 2>
810_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
811bool operator<(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
812                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
813{
814    return __lhs.compare(__rhs) < 0;
815}
816
817
818// operator >
819template<class _CharT, class _Traits>
820_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
821bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
822{
823    return __lhs.compare(__rhs) > 0;
824}
825
826template<class _CharT, class _Traits, int = 1>
827_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
828bool operator>(basic_string_view<_CharT, _Traits> __lhs,
829                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
830{
831    return __lhs.compare(__rhs) > 0;
832}
833
834template<class _CharT, class _Traits, int = 2>
835_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
836bool operator>(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
837                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
838{
839    return __lhs.compare(__rhs) > 0;
840}
841
842
843// operator <=
844template<class _CharT, class _Traits>
845_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
846bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
847{
848    return __lhs.compare(__rhs) <= 0;
849}
850
851template<class _CharT, class _Traits, int = 1>
852_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
853bool operator<=(basic_string_view<_CharT, _Traits> __lhs,
854                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
855{
856    return __lhs.compare(__rhs) <= 0;
857}
858
859template<class _CharT, class _Traits, int = 2>
860_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
861bool operator<=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
862                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
863{
864    return __lhs.compare(__rhs) <= 0;
865}
866
867
868// operator >=
869template<class _CharT, class _Traits>
870_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
871bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
872{
873    return __lhs.compare(__rhs) >= 0;
874}
875
876
877template<class _CharT, class _Traits, int = 1>
878_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
879bool operator>=(basic_string_view<_CharT, _Traits> __lhs,
880                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
881{
882    return __lhs.compare(__rhs) >= 0;
883}
884
885template<class _CharT, class _Traits, int = 2>
886_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
887bool operator>=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
888                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
889{
890    return __lhs.compare(__rhs) >= 0;
891}
892
893
894template<class _CharT, class _Traits>
895basic_ostream<_CharT, _Traits>&
896operator<<(basic_ostream<_CharT, _Traits>& __os,
897           basic_string_view<_CharT, _Traits> __str);
898
899// [string.view.hash]
900template<class _CharT>
901struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > >
902    : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
903{
904    _LIBCPP_INLINE_VISIBILITY
905    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
906        return __do_string_hash(__val.data(), __val.data() + __val.size());
907    }
908};
909
910
911#if _LIBCPP_STD_VER > 11
912inline namespace literals
913{
914  inline namespace string_view_literals
915  {
916    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
917    basic_string_view<char> operator "" sv(const char *__str, size_t __len) _NOEXCEPT
918    {
919        return basic_string_view<char> (__str, __len);
920    }
921
922#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
923    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
924    basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len) _NOEXCEPT
925    {
926        return basic_string_view<wchar_t> (__str, __len);
927    }
928#endif
929
930#ifndef _LIBCPP_HAS_NO_CHAR8_T
931    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
932    basic_string_view<char8_t> operator "" sv(const char8_t *__str, size_t __len) _NOEXCEPT
933    {
934        return basic_string_view<char8_t> (__str, __len);
935    }
936#endif
937
938    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
939    basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT
940    {
941        return basic_string_view<char16_t> (__str, __len);
942    }
943
944    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
945    basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len) _NOEXCEPT
946    {
947        return basic_string_view<char32_t> (__str, __len);
948    }
949  } // namespace string_view_literals
950} // namespace literals
951#endif
952_LIBCPP_END_NAMESPACE_STD
953
954_LIBCPP_POP_MACROS
955
956#endif // _LIBCPP_STRING_VIEW
957